Organofunctional silicone compounds are one of two types, internal and terminal depending upon the location of the silicone group.
The so-called terminal group has the organic functional groups at the alpha and omega terminus of the molecule. Typical of this class of compounds is the class of compounds currently called bis-dimethicone conforming to the following structure:
In the case where R is —(CH2)15—CH3 the compound is bis cetyl dimethicone,
The other type of compound is one in which the organofunctionality is located on non-terminal ends of the molecule. This type of compound is called a “comb” compound since the organofunctionality lies in the molecule much like the teeth of a comb. These compounds are shown in the following structure:
In the case where R is —(CH2)15—CH3 the compound is simply cetyl dimethicone,
These two classes of compounds have been known for many years. Typical patents showing these compounds and their derivatives are seen in the following patents:
There are limitations on the properties of the silicone compounds of these classes and the products are often used in different applications. The functionality of these materials is determined by the way in which they orientate in solvent. Specifically, in what conformation the lowest energy is achieved. Since oil and silicone are not soluble in each other the internal oil soluble groups rotate around the Si—O—Si bond and associate with each other in essentially spherical globules.

The result is a sphere with silicone on the perimeter and oil soluble groups in the interior.
Now consider the terminal substituted compound. Since the organofunctional groups are fixed at the end they cannot simple rotate to associate. They form what we refer to as a sandwich type association that has the lowest energy.

The molecular association results in a conformation that forms resembles a sandwich in which the bread is silicone rich and the “meat” is oily (i.e. alkyl groups).
Unlike either of these, we have surprisingly found that when a molecule has both terminal and comb groups present it forms different associations we refer to as star associations in which smaller aggregates form. If one considers these materials as tennis balls, the core is silicone and the yellow fuzzy coating is the oil phase. These small compact units have unexpected properties both in terms of tactile feel on the skin and the ability to make micro emulsions in water or oil, making them very valuable for use in personal care applications.